How to make a Portal Bridge material in Cycles?
Basically you can just mix between some emission shaders and transparent shaders based on some textures (click for larger image): 



This uses a tile able image to create the sine-wave effects. I used a procedural gradient texture and a color ramp node to create the bright edges, and a noise texture to give some basic variations.

Note that a separate emission shader is used for illuminating other objects, in order to make illuminate other objects better without over exposing the object itself.

The image texture I used was this rather poorly hand painted wave. It's probably possible to procedurally generate such a wave with some math, but I'm not sure how..



In order to create a glow/bloom effect, I would use the compositor. You can either use a quick glare node, or manually blur and add the result back to the base image. For good measure I also mixed in some ambient occlusion and some fog/depth glowy stuff.



Result:



Example .blend